Bingo.
Tony was already acting pretty forgiving about the trying to shoot him the face while brainwashed incident. That video of his parents murders that was so brutal what other human reaction could there be? Tony is not the Dalai lama. Even Steve Rogers might have snapped if there was video of Bucky strangling his beloved mother to death.
T'Challa was out for blood after his father was killed for more than half the movie and that was only tempered when he realized his rage would have caused him to kill the wrong man.
Thanks for your explaination.
t: ) and I also liked the friendship between Steve and Sam more. Bucky really didn't say much with either though - he didn't say much period.